key stroke vs keystroke

key stroke and keystroke both are nouns.

Word	Noun	Adjective	Verb	Adverb
key stroke	Yes	No	No	No
keystroke	Yes	No	No	No

As nouns, key stroke and keystroke are synonyms defined as:

key stroke and keystroke: the stroke of a key; one depression of a key on a keyboard

key stroke (noun)	keystroke (noun)
the stroke of a key; one depression of a key on a keyboard	the stroke of a key; one depression of a key on a keyboard